MATLAB 全景图切割及盒图显示的实现步骤

本文给大家分两部分介绍，第一部分通过图文的形式给大家介绍了全景图切割的代码，第二部分给大家介绍了盒图展示效果的实现代码，对MATLAB 全景图切割相关知识感兴趣的朋友，跟随小编一起看看吧

part1 全景图切割

原图：

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切割效果：

在这里插入图片描述

以下是切割部分步骤：
举这张图为例，图片格式hdr,jpg啥的都行：

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1.1 边缘剔除

有些全景图会自带白灰色边缘，若是直接进行切割便会出现如下效果：

在这里插入图片描述

这时候我们首先要对原图进行白边剔除，代码如下：

 oriPic=imread('test.hdr'); [rows,cols,~]=size(oriPic); for i=cols:-1:1 tempListR=oriPic(floor(rows/4):ceil(3*rows/4),i,1); tempListG=oriPic(floor(rows/4):ceil(3*rows/4),i,1); tempListB=oriPic(floor(rows/4):ceil(3*rows/4),i,1); if all(round(tempListR-mean(tempListR))==0)&&all(tempListR==tempListG)&&all(tempListR==tempListB) oriPic(:,i,:)=[]; else break; end end oriPic=oriPic(:,end:-1:1,:); for i=size(oriPic,2):-1:1 tempListR=oriPic(floor(rows/4):ceil(3*rows/4),i,1); tempListG=oriPic(floor(rows/4):ceil(3*rows/4),i,1); tempListB=oriPic(floor(rows/4):ceil(3*rows/4),i,1); if all(round(tempListR-mean(tempListR))==0)&&all(tempListR==tempListG)&&all(tempListR==tempListB) oriPic(:,i,:)=[]; else break; end end oriPic=oriPic(:,end:-1:1,:); for i=rows:-1:1 tempListR=oriPic(i,floor(cols/4):ceil(3*cols/4),1); tempListG=oriPic(i,floor(cols/4):ceil(3*cols/4),1); tempListB=oriPic(i,floor(cols/4):ceil(3*cols/4),1); if all(round(tempListR-mean(tempListR))==0)&&all(tempListR==tempListG)&&all(tempListR==tempListB) oriPic(i,:,:)=[]; else break; end end oriPic=oriPic(end:-1:1,:,:); for i=size(oriPic,1):-1:1 tempListR=oriPic(i,floor(cols/4):ceil(3*cols/4),1); tempListG=oriPic(i,floor(cols/4):ceil(3*cols/4),1); tempListB=oriPic(i,floor(cols/4):ceil(3*cols/4),1); if all(round(tempListR-mean(tempListR))==0)&&all(tempListR==tempListG)&&all(tempListR==tempListB) oriPic(i,:,:)=[]; else break; end end oriPic=oriPic(end:-1:1,:,:);

1.2 图像裁剪

我们要让完成的就是如下的变换和裁剪：

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这部分其实已经有较为成熟的原理和代码：
代码参考：https://stackoverflow.com/questions/29678510/convert-21-equirectangular-panorama-to-cube-map

原理参考：
http://paulbourke.net/panorama/cubemaps/#1

http://paulbourke.net/panorama/cubemaps/

原理参考文章中更加清晰的变化图：

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另：
在参考代码的基础上，对映射像素进行了插值处理，可以使图像更加平滑，原理如下：

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主要函数代码：

 function resultPic=createCubeMapFace(oriPic,id,height,width) [M,N,~]=size(oriPic); resultPic=zeros([height,width,3]); an=sin(pi/4); ak=cos(pi/4); faceTransform=[0,0; pi/2,0; pi,0; -pi/2,0; 0,-pi/2; 0,pi]; ftu=faceTransform(id,1); ftv=faceTransform(id,2); for y=0:height-1 for x=0:width-1 nx=y/height-0.5; ny=x/width-0.5; nx=nx*2*an; ny=ny*2*an; if (ftv == 0) u=atan2(nx, ak); v=atan2(ny*cos(u),ak); u=u+ftu; elseif(ftv>0) d=sqrt(nx*nx+ny*ny); v=pi/2-atan2(d,ak); u=atan2(ny,nx); else d=sqrt(nx*nx+ny*ny); v=-pi/2+atan2(d,ak); u=atan2(-ny,nx); end u=u/(pi); v=v/(pi/2); while(v<-1) v=v+2; u=u+1; end while(v>1) v=v-2; u=u+1; end while(u<-1) u=u+2; end while(u>1) u=u-2; end u=u/2+0.5; v=v/2+0.5; u=u*(N-1)+1; v=v*(M-1)+1; fv=floor(v);fv1=floor(v)+1;pv=v-fv;fv1(fv1>M)=M; fu=floor(u);fu1=floor(u)+1;pu=u-fu;fu1(fu1>N)=N; resultPic(x+1,y+1,:)=double(oriPic(fv,fu,:)).*(1-pv).*(1-pu)+... double(oriPic(fv1,fu,:)).*(pv).*(1-pu)+... double(oriPic(fv,fu1,:)).*(1-pv).*(pu)+... double(oriPic(fv1,fu1,:)).*(pv).*(pu); end end resultPic=uint8(resultPic); end

函数调用及图像存储：
这里后面长宽数值可以任意设定，但是要求长宽数值一致，如果按照当前写法，结果被存储至result文件夹：

 if ~exist('result','dir') mkdir('result'); end for i=1:6 resultPic=createCubeMapFace(oriPic,i,500,500); figure(i) imshow(resultPic) imwrite(resultPic,['result\',num2str(i),'.jpg-600']) end

另：如图所示
图片序号[1,2,3,4,5,6]分别对应图片[右，后，左，前，上，下]

在这里插入图片描述

1.3 完整代码

 function panoramic2box oriPic=imread('889027-884424860.jpg-600'); [rows,cols,~]=size(oriPic); for i=cols:-1:1 tempListR=oriPic(floor(rows/4):ceil(3*rows/4),i,1); tempListG=oriPic(floor(rows/4):ceil(3*rows/4),i,1); tempListB=oriPic(floor(rows/4):ceil(3*rows/4),i,1); if all(round(tempListR-mean(tempListR))==0)&&all(tempListR==tempListG)&&all(tempListR==tempListB) oriPic(:,i,:)=[]; else break; end end oriPic=oriPic(:,end:-1:1,:); for i=size(oriPic,2):-1:1 tempListR=oriPic(floor(rows/4):ceil(3*rows/4),i,1); tempListG=oriPic(floor(rows/4):ceil(3*rows/4),i,1); tempListB=oriPic(floor(rows/4):ceil(3*rows/4),i,1); if all(round(tempListR-mean(tempListR))==0)&&all(tempListR==tempListG)&&all(tempListR==tempListB) oriPic(:,i,:)=[]; else break; end end oriPic=oriPic(:,end:-1:1,:); for i=rows:-1:1 tempListR=oriPic(i,floor(cols/4):ceil(3*cols/4),1); tempListG=oriPic(i,floor(cols/4):ceil(3*cols/4),1); tempListB=oriPic(i,floor(cols/4):ceil(3*cols/4),1); if all(round(tempListR-mean(tempListR))==0)&&all(tempListR==tempListG)&&all(tempListR==tempListB) oriPic(i,:,:)=[]; else break; end end oriPic=oriPic(end:-1:1,:,:); for i=size(oriPic,1):-1:1 tempListR=oriPic(i,floor(cols/4):ceil(3*cols/4),1); tempListG=oriPic(i,floor(cols/4):ceil(3*cols/4),1); tempListB=oriPic(i,floor(cols/4):ceil(3*cols/4),1); if all(round(tempListR-mean(tempListR))==0)&&all(tempListR==tempListG)&&all(tempListR==tempListB) oriPic(i,:,:)=[]; else break; end end oriPic=oriPic(end:-1:1,:,:); % ========================================================================= if ~exist('result','dir') mkdir('result'); end for i=1:6 resultPic=createCubeMapFace(oriPic,i,500,500); figure(i) imshow(resultPic) imwrite(resultPic,['result\',num2str(i),'.jpg-600']) end % ========================================================================= function resultPic=createCubeMapFace(oriPic,id,height,width) [M,N,~]=size(oriPic); resultPic=zeros([height,width,3]); an=sin(pi/4); ak=cos(pi/4); faceTransform=[0,0; pi/2,0; pi,0; -pi/2,0; 0,-pi/2; 0,pi]; ftu=faceTransform(id,1); ftv=faceTransform(id,2); for y=0:height-1 for x=0:width-1 nx=y/height-0.5; ny=x/width-0.5; nx=nx*2*an; ny=ny*2*an; if (ftv == 0) u=atan2(nx, ak); v=atan2(ny*cos(u),ak); u=u+ftu; elseif(ftv>0) d=sqrt(nx*nx+ny*ny); v=pi/2-atan2(d,ak); u=atan2(ny,nx); else d=sqrt(nx*nx+ny*ny); v=-pi/2+atan2(d,ak); u=atan2(-ny,nx); end u=u/(pi); v=v/(pi/2); while(v<-1) v=v+2; u=u+1; end while(v>1) v=v-2; u=u+1; end while(u<-1) u=u+2; end while(u>1) u=u-2; end u=u/2+0.5; v=v/2+0.5; u=u*(N-1)+1; v=v*(M-1)+1; fv=floor(v);fv1=floor(v)+1;pv=v-fv;fv1(fv1>M)=M; fu=floor(u);fu1=floor(u)+1;pu=u-fu;fu1(fu1>N)=N; resultPic(x+1,y+1,:)=double(oriPic(fv,fu,:)).*(1-pv).*(1-pu)+... double(oriPic(fv1,fu,:)).*(pv).*(1-pu)+... double(oriPic(fv,fu1,:)).*(1-pv).*(pu)+... double(oriPic(fv1,fu1,:)).*(pv).*(pu); end end resultPic=uint8(resultPic); end end

1.4 其他几组切割结果

图片源自：https://www.cgmodel.com/article/9004.html

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part2 盒图展示

2.1 曲面绘制

使用surf绘制各个曲面后，并为各个曲面贴图：

 for i=1:6 oriPic.(['p',num2str(i)])=imread(['result\',num2str(i),'.jpg-600']); end [rows,cols,~]=size(oriPic.p1); [baseXY,baseZ]=meshgrid(1:cols,rows:-1:1); ax=gca;hold(ax,'on') surf(baseXY(:,end:-1:1)-(1+rows)/2,-(rows-1)./2.*ones(size(baseXY)),baseZ,'CData',oriPic.p1,'EdgeColor','none','FaceColor','interp') surf(-(rows-1)./2.*ones(size(baseXY)),baseXY-(1+rows)/2,baseZ,'CData',oriPic.p2,'EdgeColor','none','FaceColor','interp') surf(baseXY-(1+rows)/2,(rows-1)./2.*ones(size(baseXY)),baseZ,'CData',oriPic.p3,'EdgeColor','none','FaceColor','interp') surf((rows-1)./2.*ones(size(baseXY)),baseXY(:,end:-1:1)-(1+rows)/2,baseZ,'CData',oriPic.p4,'EdgeColor','none','FaceColor','interp') surf(baseXY'-(1+rows)/2,baseXY-(1+rows)/2,ones(size(baseXY)),'CData',oriPic.p6(end:-1:1,end:-1:1,:),'EdgeColor','none','FaceColor','interp') surf(baseXY'-(1+rows)/2,baseXY-(1+rows)/2,rows-1+ones(size(baseXY)),'CData',oriPic.p5(:,end:-1:1,:),'EdgeColor','none','FaceColor','interp')

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2.2 视角调整

通过设置axes属性将视角调整至盒子里面

 ax=axes('parent',fig,'position',[-0.45 -0.45 1.9 1.9]);hold(ax,'on') ax.ZLim=[0,rows+1]; ax.XLim=[0-(1+rows)/2,rows+1-(1+rows)/2]; ax.YLim=[0-(1+rows)/2,rows+1-(1+rows)/2]; ax.Color=[0 0 0]; ax.CameraPosition=[0,0,rows/2]; ax.CameraPositionMode='manual'; ax.DataAspectRatio=[1,1,1]; ax.DataAspectRatioMode='manual'; ax.Projection='perspective'; ax.CameraTargetMode='manual'; ax.CameraViewAngle = 7; ax.View=[-2.7391 90.0000]; ax.CameraTarget=[0 0 (rows-1)/2]; ax.Toolbar.Visible='on';

运行后点击那个三位旋转按钮即可开始漫游

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此时的盒图是无缝隙版本，有缝隙版放在后面

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2.3 完整代码

无缝隙版：

 function showBox for i=1:6 oriPic.(['p',num2str(i)])=imread(['result\',num2str(i),'.jpg-600']); end [rows,cols,~]=size(oriPic.p1); [baseXY,baseZ]=meshgrid(1:cols,rows:-1:1); fig=figure('units','pixels','position',[300 80 500 500],... 'Numbertitle','off','menubar','none','resize','off',... 'name','box'); ax=axes('parent',fig,'position',[-0.45 -0.45 1.9 1.9]);hold(ax,'on') ax.ZLim=[0,rows+1]; ax.XLim=[0-(1+rows)/2,rows+1-(1+rows)/2]; ax.YLim=[0-(1+rows)/2,rows+1-(1+rows)/2]; ax.Color=[0 0 0]; ax.CameraPosition=[0,0,rows/2]; ax.CameraPositionMode='manual'; ax.DataAspectRatio=[1,1,1]; ax.DataAspectRatioMode='manual'; ax.Projection='perspective'; ax.CameraTargetMode='manual'; ax.CameraViewAngle = 7; ax.View=[-2.7391 90.0000]; ax.CameraTarget=[0 0 (rows-1)/2]; ax.Toolbar.Visible='on'; surf(baseXY(:,end:-1:1)-(1+rows)/2,-(rows-1)./2.*ones(size(baseXY)),baseZ,'CData',oriPic.p1,'EdgeColor','none','FaceColor','interp') surf(-(rows-1)./2.*ones(size(baseXY)),baseXY-(1+rows)/2,baseZ,'CData',oriPic.p2,'EdgeColor','none','FaceColor','interp') surf(baseXY-(1+rows)/2,(rows-1)./2.*ones(size(baseXY)),baseZ,'CData',oriPic.p3,'EdgeColor','none','FaceColor','interp') surf((rows-1)./2.*ones(size(baseXY)),baseXY(:,end:-1:1)-(1+rows)/2,baseZ,'CData',oriPic.p4,'EdgeColor','none','FaceColor','interp') surf(baseXY'-(1+rows)/2,baseXY-(1+rows)/2,ones(size(baseXY)),'CData',oriPic.p6(end:-1:1,end:-1:1,:),'EdgeColor','none','FaceColor','interp') surf(baseXY'-(1+rows)/2,baseXY-(1+rows)/2,rows-1+ones(size(baseXY)),'CData',oriPic.p5(:,end:-1:1,:),'EdgeColor','none','FaceColor','interp') end

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有缝隙版：

 function showBox2 for i=1:6 oriPic.(['p',num2str(i)])=imread(['result\',num2str(i),'.jpg-600']); end [rows,cols,~]=size(oriPic.p1); [baseXY,baseZ]=meshgrid(1:cols,rows:-1:1); fig=figure('units','pixels','position',[300 80 500 500],... 'Numbertitle','off','menubar','none','resize','off',... 'name','box'); ax=axes('parent',fig,'position',[-0.45 -0.45 1.9 1.9]);hold(ax,'on') ax.ZLim=[0,rows+1]; ax.XLim=[0-(1+rows)/2,rows+1-(1+rows)/2]; ax.YLim=[0-(1+rows)/2,rows+1-(1+rows)/2]; ax.Color=[0 0 0]; ax.CameraPosition=[0,0,rows/2]; ax.CameraPositionMode='manual'; ax.DataAspectRatio=[1,1,1]; ax.DataAspectRatioMode='manual'; ax.Projection='perspective'; ax.CameraTargetMode='manual'; ax.CameraViewAngle = 7; ax.View=[-2.7391 90.0000]; ax.CameraTarget=[0 0 (rows+1)/2]; ax.Toolbar.Visible='on'; surf(baseXY(:,end:-1:1)-rows/2,-rows./2.*ones(size(baseXY)),baseZ,'CData',oriPic.p1,'EdgeColor','none','FaceColor','interp') surf(-rows./2.*ones(size(baseXY)),baseXY-(1+rows)/2,baseZ,'CData',oriPic.p2,'EdgeColor','none','FaceColor','interp') surf(baseXY-(1+rows)/2,rows./2.*ones(size(baseXY)),baseZ,'CData',oriPic.p3,'EdgeColor','none','FaceColor','interp') surf(rows./2.*ones(size(baseXY)),baseXY(:,end:-1:1)-(1+rows)/2,baseZ,'CData',oriPic.p4,'EdgeColor','none','FaceColor','interp') surf(baseXY'-(1+rows)/2,baseXY-(1+rows)/2,zeros(size(baseXY)),'CData',oriPic.p6(end:-1:1,end:-1:1,:),'EdgeColor','none','FaceColor','interp') surf(baseXY'-(1+rows)/2,baseXY-(1+rows)/2,rows+ones(size(baseXY)),'CData',oriPic.p5(:,end:-1:1,:),'EdgeColor','none','FaceColor','interp') end

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